Electric motor.



G, H. ELECTRIC MOTOR. APPLICATION FILED T11R34, 1910.

EFEIL.

Patented Apr. 18, 1911.

20 a novel form of insulation for use 25 ing my 45 manner of constructing UNITED sraras rare GEORGE H..PFEIL, F SWISSVALE, PENNSYLVANIA, ASSIGNOR TO THE UNION SW ITCH SW'ISSVALE, PENNSYLVANIA, ACORPORATION OF PENN.-

& SIGNAL COMPANY, OF SYLVA'NIA.

T OFFICE.

ELECTRIC MGTOIR.

To all whom it may concern.

V Be it known that I, Gsorcs Pram, a citizen of the United States, residmg 1n the borough of Swissvale, county of Allegheny, 5 and State of-Pennsylvania, have invented a and more-particularly to the bushing by means of which the commutator is insulated from the armature shaft of such motors.

In the manufacture of electric motors for commercial purposes, it is sometimes re quired that the armature should withstand a break-down test of high voltages (3,000 volts and over). between the shaft and the segments forming the commutator.

An object of my invention is to provide between motors,

the rethe commutator and shaft of such which will enable them to withstand quired break down tests.

I will describe a form of bushing embodyinvention, and then point out the novel features thereof in claims.

In the accompanying drawings, Figure l isa cross-sectional view showing amotor commutator and-shaft having one form of [K 1nsulat1ng bushing embodying my lnventlon. Fig. '2 1s a new showlng 1n section the two telescoping portions of the bushing illustrated in Fig. 1. Figs. 3 and 4 are views showing the developed forms of the parts 7 and 8 of-Fig. 2.

Referring now to Fig. 1, the reference character 6 designates a shaft of an electric motor, upon which shaft is mounted a commutator composed of a plurality of seg- 40 ments 9. Between the commutator segments and the shaft are two-telescoping portions of insulating material designated by land 8. These two portions are shown separately and more clearly in Fig. 2. A preferred these sleeves or portions of. bushings is as follows, although I do not. desire to, limit myself to any particular means'of construction, or to any particular insulating material. The flatinsulating material is first cut or punchedinto blanks of approximately-the forms shown in Figs. 3 and 4, a series of parallel slits 15 being out along the straight edge of each. The sleeves the commutator bars 9 to .of dynamo-electric machines,

are then formed by rolling these Specification of Letters Patent. Application filed February 4, i910.

Patented Apr. 18, lifiiilt serial No. 542,033.

blanks over mandreis and flaring out the ends to form the flanges, as allowed by the slits The flared ends are then made substantially solidv by placing one of the wash ers 16 and 11 of insulating material on each side of the flange, When the'whole is placed in a mold and heated under pressure. Referring again to Fig. 1, it will be seen. that when the commutator is assembled, the sleeve 8 is slipped overthe sleeve 7, and a prac ically continuous insulating bushing is obtained. The overlapping distance around the ends of the sleeves where they join is equal te,or greater than, the distance from the shaft 6 around the outside, hence there is little probability of an electrical break-down within the commutator.

Having thus claim:

1. An insulating bushing for commutators of dynamoelectric machines, comprising two sections adapted to overlap at their meeting edges, each section comprising a sleeve portion and an inwardly inclined end flange adapted to retain the commutator seg ments.

described my invention, I

2. An insulating bushing for commutators I of dynamo-electric machines comprising two sections adapted to overlap at their meeting .edges, each section comprising a sleeve portion and an expanded end flange integral therewith, the said flange being slanted inwardly toward the middle of the bushing to retain the commutator segments.

3. An insulating bushing for commutators of dynamo-electric machines, comprising two partially telescoping port-ions, each comprising a sleeve and an end flange substantially integral, the said flange being sloped inwardly to retain the commutator segments. 4:. An insulating bushing for commutators comprising a sleeve formed of insulating material and having at one end an internal cylindrical recess, and a similar sleeve having at one end an external reduced portion adapted to fit into the recess of the first-mentioned sleeve, thereby forming a substantially continuous bushing. v

5. An insulating bushing for commutators of dynamo-electric machines, comprising a sleeve of insulating material having at one end an expanded flange and at the other end an internal cylindrical recess, and a similar sleeve having at one end an expanded flange and at the other end an externally reduced portion adapted to it into the recess of the first-mentioned sleeve thereby forming a substantially continuous bushing, the expanded flanges being sloped toward the middle of the bushing to retain the commutator segments.

6.111 a commutator For dwnamo-electric machines the combination, segments having triangular projections or lugs, of an insulating bushing comprising two partially telescoping portions, each por tion comprising; a sleeve and an end flange integral therewith, the said flanges being sloped inwardly to retain, the triangular projections on the segments.

7 In a connnutator for dynamo-electric machines the eonhination, with commutator with commutator segments having triangular projections or lugs. of an insulating bushing therefor comprising a sleeve of insulating: material having-at. one end an expanded flange and at the other end an internal cylindrical recess, and a similar sleeve having at one end an expandml flange and at the other end an externally reduced portion adapted to fit into the said recess in the first mentioned sleeve, thereby forming a substantially continuous bushing, the said expanded flanges being sloped inwardly to retain the triangular projections on the segments.

ln testimony whereof, I. have signed my name to this specification in the presence of two subscribed Witnesses.

GEORGE H. PFEIL. \Yitnesses:

.T. G. SOHRENDER, ll. Fnnonni'o Howl-um, 

